The invention relates to a novel class of compounds which have a structures related to naturally and synthetically occurring chalcones, as well as to methods for preparation of such compounds and to pharmaceutical uses thereof.
The compound 1,3-diphenyl-2-propene-1-one is known by the trivial name chalcone. Many naturally occurring flavanoids share structural features with chalcone and are referred to by the generic term xe2x80x9cchalconesxe2x80x9d. Also certain flavanoids, including ones which are classified as chalcones, have recently been demonstrated to have anticancer activity (Cancer Research 48, 5754, 1988) and chemopreventive activity in some tumours (J. Nat. Prod. 53, 23, 1990).
In particular, quercetin, an ubiquitous flavonoid found in plants, has been shown to act on the proliferation of human leukemic cells (Br. J. of Haematology, 75, 489, 1990) and on other cell lines (Br. J. Cancer 62 94, 942, 1990; Int. J. Cancer, 46, 112, 1990; Gynaecologic Oncology, 45, 13, 1992) and to possess a synergic action with common antiblastic drugs.
In addition, some natural or synthetic chalcones, described in our International Patent Publication No. WO 9117749 and in International Patent Publication No. WO 96/19209 (Baylor College of Medicine) have proved to have a significant antiproliferation activity on a variety of different cell lines.
Although the mechanism of action of the antiproliferative activity of flavonoids and chalcones is still unknown, it is believed to be linked to the interaction of these compounds with type II estrogen receptors.
The action in vivo of these polyphenol substances is certainly much more complicated. All these compounds are generally characterised by an almost complete insolubility in water and, in vivo, by a very poor bioavailability linked to a rapid metabolism of phenols and a marked affinity for lipids and proteins.
Surprisingly, it has now been found that certain novel chalcones, chalcone derivatives and chalcone analogues, in particular ones in which the phenyl ring in the 1-position is substituted or replaced by rings containing one or more heteroatoms, possess a greater antiproliferation activity both on sensitive cancerous cells and on cells which are resistant to common chemotherapeutic drugs, including the latest generation anti-neoplastic agents, pacitaxel and docetaxel.
Thus according to one aspect of the present invention, there is provided a compound of Formula (I): 
or a pharmaceutically acceptable salt or solvate thereof wherein:
Ar represents:
a substituted or unsubstituted, (preferably aromatic), carbocyclic or heterocyclic group, said carbocyclic or heterocyclic group containing from 5 to 10 ring atoms, said ring atoms forming one or two rings, wherein the or each ring contains 5 or 6 ring atoms, any heteroatoms being selected from N, O and S, any substituents on the Ar group being independently selected from the group consisting of:
(a) Cl, (b) Br, (c) F, (d) OH, (e) NO2, (f) CF3, (g) C1-4 lower alkyl (in particular CH3), (h) SCH3, (i) NHCOCH3, (j) N(R6)(R8) wherein R6 and R8 are the same or different and each represents H or lower C1-4 alkyl, (k) OR10 wherein R10 represents a saturated or unsaturated lower C1-6 straight or branched hydrocarbyl group which may be unsubstituted or substituted by 1, 2 or 3 substituents selected from:
Cl, Br, F, OMe, NO2 and CF3,
xe2x80x83and (I) xe2x80x94OCOR11, wherein R11 represents a saturated or unsaturated lower C1-6 straight or branched hydrocarbyl group or a phenyl group;
R represents
OH, OR10 or OCOR11, wherein R10 and R11 are as defined above; and R1 represents H or a lower C1-6 straight or branched hydrocarbyl group which may be unsubstituted or substituted by 1, 2 or 3 substituents selected from Cl, Br, F, OMe, NO2 and CF3.